As mentioned in our preview that launched earlier today, developer Eidos Montreal is putting the finishing touches on the upcoming Deus Ex: Human Revolution downloadable content 'The Missing Link.' Scheduled to launch sometime in October, the DLC will take place during a three-day span missing from the life of protagonist Adam Jensen during the main campaign of the game.

Edios Montreal game designer Antoine Thisdale visited the Shacknews office to discuss some of the changes made for 'The Missing Link,' the corporate culture at the Montreal studio, and more.

Note: Thisdale outlines where 'The Missing Link' fits in the story of Deus Ex: Human Revolution. Though he does not spoil the story or the ending, we've added a spoiler warning for those that don't want to know the basics.

As Thisdale sits back waiting for our camera man to record, Johnny Fournier from Square Enix sits back and plays on a monitor behind Thisdale. Like the team at Eidos Montreal, Fournier has "lived and breathed the game for the past few years," a PR rep tells me.

"Are you dancing?" Thisdale asks, looking behind him at the screen. Thisdale is referring to the countless videos online of Adam Jensen's character model swaying from side-to-side--the animation for changing perspective in cover--but to music.

"Those videos are amazing," I laugh. They agree. It's one of those things that developers don't pay attention to during development. After working on a game for years, it's difficult to discover something new. When it was put in the hands of gamers, they immediately saw the potential hilarity in the animation.

Deus Ex: Human Revolution had been in development for quite a while. In the span of four years I covered the game at three major outlets, personally. I first covered the reveal on Joystiq, previewed it for GamePro Magazine, and reviewed it for Shacknews. Either it took a while, or I get around.

"I'm a fan of 'Jensen Needs a New Mirror,'" Thisdale says, referencing another YouTube clip.

When Eidos Montreal opened its doors to me for a preview event nearly two years ago the team was still dealing with construction on its two-floor office in the heart of Montreal, Canada. Since then, the team has grown to "about 150."

"That was a big thing for Stéphane [D'Astous], our big boss, to never grow too big," Thisdale tells me. "It's not about putting, like, 350 people working on a project. It's about the quality."

While 'The Missing Link' injects itself into a lost piece of Human Revolution, the content isn't cobbled together from spare parts. "It's all new content. We didn't recycle anything." Thisdale tells me, mentioning that Eidos Montreal was able to add technical enhancements to the game that were unavailable during the development stages of Human Revolution.

"We have better lighting now," he explains. "Better textures and the shaders respond to the lighting better. So, the characters look really good. Everybody that worked on [The Missing Link] is actually a veteran from Human Revolution. Lots of experience went into 'The Missing Link.'" Eidos Montreal even went so far as to get new music for the DLC, created by Human Revolution composer Michael McCann.

When the content is available, players will execute 'The Missing Link' from the Deus Ex: Human Revolution's main menu. This allows anyone to play the content when they decide to, not forcing them to get to a certain point in the retail game. Thisdale promises that the content won't spoil the story of Human Revolution, rather it "reinforces" the narrative while revealing more detail on some of the conspiracies and enemies in the universe.

Deus Ex: Human Revolution 'The Missing Link' DLC is coming this October for the PC, Xbox 360, PlayStation 3, and via the OnLive Cloud Gaming service.